efi: Export Runtime Configuration Interface table to sysfs

System firmware advertises the address of the 'Runtime
Configuration Interface table version 2 (RCI2)' via
an EFI Configuration Table entry. This code retrieves the RCI2
table from the address and exports it to sysfs as a binary
attribute 'rci2' under /sys/firmware/efi/tables directory.
The approach adopted is similar to the attribute 'DMI' under
/sys/firmware/dmi/tables.

RCI2 table contains BIOS HII in XML format and is used to populate
BIOS setup page in Dell EMC OpenManage Server Administrator tool.
The BIOS setup page contains BIOS tokens which can be configured.

Signed-off-by: Narendra K <Narendra.K@dell.com>
Reviewed-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

efi: Add 'systab' information to Documentation/ABI

It's not clear right now that the order in which entries are displayed
in /sys/firmware/efi/systab actually forms an ABI that userspace tools
rely upon.

Document the ABI along with the userspace tool that cares.

Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ivan Khoronzhuk <ivan.khoronzhuk@globallogic.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

efi: Export more EFI table variables to sysfs

Export fw_vendor, runtime and config table physical addresses to
/sys/firmware/efi/{fw_vendor,runtime,config_table} because kexec kernels
need them.

From EFI spec these 3 variables will be updated to virtual address after
entering virtual mode. But kernel startup code will need the physical
address.

Signed-off-by: Dave Young <dyoung@redhat.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>